1. Field of the Invention
The present invention relates to a device for the delayed disconnection or switching-off of the drive of cutting mechanisms of paper shredders, wherein the switching-on process of the cutting mechanisms is automatically triggered predominantly by the insertion of the materials to be shredded into the feed shaft.
2. Description of the Related Art
In cutting mechanisms of paper shredders, the delayed disconnection of the drive has the purpose of ensuring that the drive always stops only after the cutting mechanism has been cleared or cleaned, i.e., the paper particles, dust resulting from cutting, etc., have left the cutting mechanism, and primarily of ensuring that the respective document has been completely destroyed or shredded.
In order to achieve this, electronically acting components have already become known in actual practice which are provided for the drive control. However, these components have the specific disadvantage that they are relatively expensive.
Also known in the art are pneumatic devices which operate with an air cylinder and delay valve. In addition to the disadvantage of a hard switching-on process, this type of construction also has the specific disadvantage that it is relatively expensive and that the many fine mechanical structural elements are susceptible to trouble. In addition, the electronic and pneumatic delay elements which have thus far become known in the art have the principal disadvantage that the duration of the after-running time of the cutting mechanism must be preadjusted empirically; however, since it is generally known that depending on the type of paper, the "self-cleaning" time of the cutting mechanisms varies widely and takes particularly long in the case of very thin paper, the systems which have become known in the art always constitute a compromise solution which is not very effective.